Total lymphoid irradiation, a potent immunosuppressive agent used to treat Hodgkin's disease for the past 15 years, and joint irradiation will be explored as modalities in the treatment of rheumatoid arthritis. Total lymphoid irradiation (TLI) will be studied in animal models of immunologically induced arthritidies including (a) rat adjuvant polyarthritis, (b) rabbit bacterial cell wall arthritis and, (c) rabbit antigen induced arthritis. The investigations will determine the lymphoid organs necessary to include in the fields and the optimal irradiation necessary to induce remission. These findings will provide direction for a clinical investigation already underway involving patients with rheumatoid arthritis receiving TLI. Joint irradiation as an alternative to surgical synovectomy will be performed as a pilot project on 12 patients with rheumatoid arthritis. The three animal models will be used to provide direction for this study. Histopathologic studies will be performed at intervals after irradiation for joint irradiation and TLI treated animals. Selective irradiation of lymph nodes, thymus, spleen and bone marrow will be used to study mechanisms of immune arthritis on a cellular basis. Lymphocyte type and function will be correlated with remission of arthritis after radiotherapy in animal models of inflammatory arthritis.